It's way too early to conclude that the success of Apple's iPad has slowed down netbook sales, a retail analyst said today.

"Could there be some cannibalization of netbook sales by the iPad?" asked Stephen Baker, analyst with the NPD Group. "Sure. But it's too soon to tell."

Baker was reacting to reports Thursday quoting Wall Street analyst Katy Huberty of Morgan Stanley, who claimed iPad sales had put a major dent in the year-over-year sales growth of netbooks, the small, inexpensive Windows-based notebooks that took the market by storm in 2009.

According to Huberty, netbook growth slowed dramatically at the first of the year, with year-over-year increases plummeting to 68% in January from 179% in December 2009, then falling further. In April, netbook sales were just 5% over the same month a year ago.

"Certainly the growth rate is coming down," said Baker. "But that's logical. In 2009, netbook sales were a growth story against nothing (in the year before). So it's really a matter of where we are in the development of the product. I'd say it's very difficult at this stage to attribute declining growth of netbooks to the iPad."

Netbooks' share of the overall notebook market has stabilized in the high-teens during the first months of 2010, Baker added, so it's not as if netbooks have suddenly vanished from the landscape. NPD collects sales data from U.S. retail brick-and-mortar stores, as well as from some leading online outlets, including Amazon.com and Apple's own e-store.

Rather than credit the iPad for the cooling of netbook sales, Baker gave a nod to slightly-more expensive notebooks running Windows. The sub-$500 notebook category now outsells netbooks.

"The development of the under-$500 notebook market is the biggest story of 2009 and early 2010," said Baker. "For a little more money, sometimes just $50 or so, consumers can buy a full notebook with a full-sized keyboard, a 15-in., sometimes a 17.-in. screen, with higher resolution [than a netbook]. That's how the notebook makers have kept things from dropping into the very bottom of the market."

Sub-$500 notebooks currently account for about 25% of all sales, Baker said.

"Netbooks were a great product at the right time," he said, referring to 2009's economic doldrums. But their time may have ended.

That's not to say Apple's iPad isn't doing well or can't go head-to-head with netbooks for consumers' credit cards. Last Monday, Apple announced that it had sold one million tablets in the first 28 days of availability.

By the end of this month, Apple will likely have sold 1.5 million iPads, said Yankee Group analyst Carl Howe in a post to his company's blog Wednesday, putting the tablet in the record books for reaching $1 billion in sales faster than any other consumer product.

"The iPad is very competitive with netbooks," echoed Baker. NPD's consumer surveys with netbook owners and prospective iPad buyers have shown "very similar responses about what they expect to do with the device," Baker said.

The slowing growth of netbook sales, and the ability of traditional notebook makers to shift some buyers to more expensive models have also slowed the decline in average selling prices (ASPs), a number that plunged last year to OEMs' dismay. In March, for example, ASPs were only 5% lower than the same month a year ago, compared to much of 2009 when ASPs were regularly down 15%.

"It's getting to the point, at least in the mainstream market, that there's not much more with pricing that you can do," Baker said.